Dennis Baron traces the odd history of futile attempts to concoct a gender-neutral pronoun:

Every once in a while some concerned citizen decides to do something about the fact that English has no gender-neutral pronoun. They either call for such a pronoun to be invented, or they invent one and champion its adoption. Wordsmiths have been coining gender-neutral pronouns for a century and a half, all to no avail. Coiners of these new words insist that the gender-neutral pronoun is indispensable, but users of English stalwartly reject, ridicule, or just ignore their proposals.